Gera A, Cohen J, Salomon R, Raccah B
Department of Virology, Agricultural Research Organization, The Volcani Center, Bet Dagan 50250, Israel.
Plant Dis. 1998 Jan;82(1):127. doi: 10.1094/PDIS.1998.82.1.127B.
During March 1997, 20 to 30% of field-grown onion (Allium cepa), observed in Bet Shean Valley, Israel, had unusual viral symptoms of straw-colored ringspots on leaves and flower stalks. Leaf samples were analyzed by transmission electron microscopy (EM) of leaf dip preparations. Typical tospovirus-like particles were observed only with samples taken from symptomatic plants. Crude sap from symptomatic tissue was mechanically transmitted to Nicotiana benthamiana, Chenopodium quinoa, and Gomphrena globosa. On inoculated plants of N. benthamiana, chlorotic spots developed on inoculated leaves, followed by systemic necrosis, 4 and 7 days post inoculation (DPI), respectively. On inoculated plants of C. quinoa and G. globosa, necrotic local lesions developed by 4 to 5 DPI. EM studies with ultrathin sections of infected onion and N. benthamiana leaves revealed the presence of tospovirus-like particles. Virus was purified from mechanically infected N. benthamiana and identified as Iris yellow spot tospovirus (IYSV) by Western blots (immunoblots) and enzyme-linked immunosorbent assay (ELISA) (anti-IYSV antiserum was provided by D. Peters, Wageningen, the Netherlands). A high incidence of the disease observed in the surrounding fields and in other onion-growing areas in Israel was associated with large populations of the onion thrips (Thrips tabaci). Although characteristic symptoms have been noted on a frequent basis, effects on yield have yet to be determined. IYSV is known to occur in the Netherlands, where it has been occasionally detected in Iris (1) and leek (A. Porrum) (J. Verhoeven, personal communication). The detection of IYSV in Israel and the wide distribution of thrips in the natural vegetation may be an important constraint on onion and other bulb-crop production in Israel. Reference: (1) A. F. L. M. Derks and M. E. C. Lemmers. Acta Hortic. 432:132, 1996.
1997年3月期间，在以色列贝特谢安山谷观察到，田间种植的洋葱（葱属植物）中有20%至30%出现了异常的病毒症状，叶片和花茎上有稻草色的环形斑点。通过对叶浸制剂进行透射电子显微镜（EM）分析叶样本。仅在从有症状植株采集的样本中观察到典型的番茄斑萎病毒属样颗粒。有症状组织的粗汁液通过机械接种传播给本氏烟草、藜麦和千日红。在接种的本氏烟草植株上，接种叶片在接种后4天和7天分别出现褪绿斑点，随后出现系统性坏死。在接种的藜麦和千日红植株上，接种后4至5天出现坏死局部病斑。对感染的洋葱和本氏烟草叶片超薄切片进行的EM研究揭示了番茄斑萎病毒属样颗粒的存在。从机械感染的本氏烟草中纯化病毒，并通过蛋白质免疫印迹（免疫印迹）和酶联免疫吸附测定（ELISA）（抗IYSV抗血清由荷兰瓦赫宁根的D. Peters提供）鉴定为鸢尾黄斑番茄斑萎病毒（IYSV）。在以色列周边田地和其他洋葱种植区观察到该病的高发病率与大量洋葱蓟马（西花蓟马）有关。尽管经常注意到特征性症状，但对产量的影响尚未确定。已知IYSV在荷兰存在，在那里偶尔在鸢尾（1）和韭菜（葱属植物）中检测到（J. Verhoeven，个人交流）。在以色列检测到IYSV以及蓟马在自然植被中的广泛分布可能是以色列洋葱和其他球茎作物生产的一个重要限制因素。参考文献：（1）A. F. L. M. Derks和M. E. C. Lemmers。《园艺学报》432:132，1996年。
